1. Field of the Invention
This invention relates to methods for communication, and more particularly to improved methods and systems for payment of roaming charges for a mobile telephone.
2. Description of the Related Art
The use of wireless or mobile communication devices has increased greatly in recent years. Wireless communications are generally transmitted between devices by using radio frequency (RF) technology. Wireless communications include communications that are transmitted through wireless units such as cellular telephones, mobile telephones, car telephones, personal communication service (PCS) units, and pagers. Other wireless communication devices may also include, for example, appropriately equipped computers and computer peripherals.
A wireless communication device is particularly useful to a person on the move. To serve the needs of such persons, wireless communications systems have evolved into seamless roaming networks that allow wireless telephone users to receive and to initiate telephone calls both from within their “home” service network and from within a “roaming” service network. A wireless telephone roams within a roaming wireless service network whenever the wireless telephone is located outside of the geographical area that is served by its usual, or “home,” wireless service network.
Numerous technical and administrative obstacles had to be overcome before a subscriber of one wireless service network could transparently receive wireless communication services from another wireless service network. For example, multilateral operating agreements had to be negotiated between service providers to standardize communications between the dissimilar switching systems of the different networks. Most importantly, definitions, common signaling protocols and common signaling message formats for exchanging and handling messages between the different switching systems had to be developed and adapted by all participating wireless service providers.
FIG. 1 is a schematic drawing that illustrates the basic components of a conventional wireless network. A basic description of a wireless telephone system is disclosed in U.S. Pat. No. 6,560,455, which is hereby fully incorporated by reference. The wireless network 100 includes a wireless telephone 114 that places or receives wireless telephone calls by transmitting and receiving RF signals through the base stations 116, 118. Typically, the wireless telephone 114 communicates with whichever base station 116, 118 provides the strongest signal.
Each base station 116, 118 transmits and receives wireless signals within a wireless communication coverage area 122, 124, often called a cell. Although only two base stations 116, 118 are depicted in FIG. 1, it should be recognized that the wireless network 100 may include many more than just two base stations. Each base station 116, 118 is connected to a Mobile Telephone Switching Office (MTSO) 126, 128 through landlines or other communication links, such as microwave communication systems. The MTSOs 126, 128 are further connected to the Public Switched Telephone Network (PSTN) 112, which is the wireline telephone system. It should be recognized that more than one base station 116, 118 is typically connected to an MTSO 126, 128.
The wireless telephone 114 shown in FIG. 1 is a conventional mobile telephone having a transceiver and an antenna that enables it to communicate with the base stations 116, 118. The MTSO 126, 128 is typically a conventional digital telephone exchange that provides wireline-to-mobile, mobile-to-wireline, and mobile-to-mobile telephone call connections. The MTSO 126, 128 also performs other functions, including, for example, receiving process status data from controllers at the base stations 116, 118 regarding the wireless telephone 114; handling and switching calls between the communication coverage areas 122, 124; processing diagnostic information; and compiling billing information. When the wireless telephone 114 passes from one communication coverage area 122 to another 124, the MTSO 126 performs a “hand-off” that allows the wireless telephone 114 to be continuously serviced in an apparent seamless manner.
The wireless network 100 identifies the wireless telephone 114, for call completion and billing purposes, by an assigned unique identity 132 that is stored in the memory of the wireless telephone 114. The identity 132 comprises a Mobile Identification Number (MIN) and an Electronic Serial Number (ESN) and may include a System Identification Code (SID). The MIN is the recognized telephone number, typically comprising an area code and a seven digit number, that is dialed by a person trying to place a telephone call to the wireless telephone 114. The MIN is assigned by the home network provider and may be easily changed at the request of the user. The ESN is assigned to the wireless unit 114 by the manufacturer and cannot be changed. The combination of the ESN and the MIN uniquely identifies each wireless telephone 114. Additionally, most providers of wireless network services within a market are assigned a SID that may be entered into the memory of the wireless unit to identify the home network service provider of the wireless telephone 114. Network service providers that have been assigned a SID typically broadcast their SID throughout their network. Then, if a wireless telephone has stored a SID in its memory, the wireless telephone can compare the SID that is being broadcast throughout the network where the wireless telephone is currently located with the SID that is stored in its memory to determine whether it is operating within its home network or whether it is operating as a roamer within a network of another service provider.
In the current North American cellular system, any given market area may be serviced by up to two competing wireless service providers, each assigned to different groups of frequencies through which services are provided. The assigned frequency sets are generally referred to as “A band frequencies” and “B band frequencies.” The A band frequencies are typically reserved for the non-wireline service providers and the B band frequencies are typically reserved for the incumbent wireline service providers.
Operation of the wireless device under roaming conditions is often under the control of the wireless device user. The user may select whether the wireless device will operate in a Home System Only, A Band Only, B Band Only, A Band Preferred, or B Band Preferred operating mode. The user typically controls the system preference and mode operation through menu choice or selection. However, sometimes the home service provider may program the wireless device with a list of “negative” SID's from which the wireless device may not receive service. Negative SID's are fully disclosed in U.S. Pat. No. 4,916,728 issued to Blair and in U.S. Pat. No. 5,442,806 issued to Barber, which are hereby fully incorporated by reference.
The wireless network 100 must be capable of identifying roaming wireless telephones within its system. The wireless network 100 determines whether a wireless telephone 114 is roaming by examining the unique identity 132, which is the ESN and the MIN, of the wireless telephone 114. The wireless telephone 114 transmits its unique identity 132 to the MTSO 126, 128 during a registration process as is known in the art. The MTSO 126, 128 compares the unique identity 132 of the wireless telephone 114 with a list of unique identities contained within a Home Location Register 138 (HLR). The HLR 138 is a database used for the management of wireless telephone subscribers of the local wireless network and contains, for example, the unique identities of each subscriber, the name and address of authorized persons, billing information, and access rights to premium subscription services, such as caller ID or voice mail. If the unique identity 132 of the wireless telephone 114 is not found within the HLR 138, then the wireless network 100 determines that the wireless telephone 114 is not a subscriber to the wireless network 100, but is instead a roaming wireless telephone.
Whenever the MTSO 126, 128 determines that a wireless telephone 114 is roaming, the MTSO 126, 128 contacts the HLR 136 of the home service provider of the wireless telephone 114. The procedure for contacting the home service provider is well known in the art. By return message to the MTSO 126, 128, the home HLR 136 of the roaming wireless telephone 114 provides relevant information concerning the roaming wireless telephone 114, such as the subscriber's feature list and any calling restrictions. This information is stored in the Visitor Location Register (VLR) 134. The VLR 134 is used to identify the mobile device 114 as long as it is roaming within the wireless network 100.
Users of wireless telephones are concerned about the high charges incurred when they are using their wireless telephones in a roaming network. Roaming charges may include, for example, a base rate for roaming, any associated long distance charges, and premium per minute charges as well. Because the incurred charges for roaming are so high, many users minimize using their wireless telephones whenever they are outside of their home network. This is an inconvenience for users accustomed to using their wireless telephones on a regular basis. For those users who must use their wireless telephones while roaming, i.e., for business travelers, a high business expense is incurred.
Furthermore, it is not just the wireless telephone users that suffer from the high roaming charges. The wireless network providers are also damaged because the roaming networks lose revenues that may otherwise be collected if roaming wireless telephone users were more inclined to use their wireless telephones. If the roaming expenses charged to roaming wireless telephone users could be reduced, users of roaming wireless telephones would increase their usage, thereby increasing the revenues that would be generated for the roaming wireless service provider. Accordingly, there is a need for methods and systems that provide an efficient and cost effective means for delivering roaming services to users of roaming wireless devices.